Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, idempotentHint, openWorldHint=false, and destructiveHint=false, so the safety profile is covered. The description adds genuinely new behavioral context: geographic coverage (main US, Canadian, and UK lanes) and the graceful not-covered fallback. It does not describe response ordering or granularity beyond the field list, keeping it out of the 5 band.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences, zero filler. The return payload is front-loaded so an agent knows immediately what it gets, and the usage/fallback sentence follows. Every clause earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With no output schema, the description correctly carries the burden of telling the agent what comes back, and it does so by enumerating the returned facts. Coverage limits and the not-covered behavior round out what an agent needs before calling.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100% and both parameters carry their own descriptions, including the 'Austin' / 'Austin, TX' format example. The description's 'names both ends of a move' restates what the schema already defines, adding little syntax or format guidance beyond it. Baseline 3 applies when the schema does the heavy lifting.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description names a specific resource (a city-to-city moving lane) and enumerates exactly what is returned: driving miles/hours, research cost range by home size, Census household flow between states, and the page URL. That specificity lets an agent distinguish this lookup from siblings like estimate_moving_cost or find_movers without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It gives a clear trigger ('Use it when someone names both ends of a move') and an explicit negative case ('returns a clear not-covered message otherwise'), which is a real when-not condition. It stops short of naming alternatives it should be preferred over (e.g. estimate_moving_cost), so it falls just below the top band.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.